Many vehicles in the future will be driven electrically, with a smaller or larger battery serving as the energy store. Until now, electrical means of transportation have been based on the use of large-volume batteries as energy stores. In this context, the size of the battery used plays a central role since it has a highly determining influence on the costs and on the entire weight of the vehicle. For this reason, the objective is to use a battery which is as small and lightweight as possible in order therefore to save weight, space and costs.
In order to be able to use the largest possible proportion of energy from the battery for the electric drive, the battery should as far as possible be kept at the temperature level which is optimum for it, regardless of the respective external temperature. Furthermore, controlling the temperature of the passenger compartment of the vehicle also requires electrical energy, which is then no longer available to drive the electric vehicle. Up to 50% of the drive energy is lost as a result of comfort functions such as air-conditioning in the summer and heating in the winter, and this significantly reduces the range of the electric vehicle.
Electric vehicles are in the development phase. Until now, in order to increase the range of electric vehicles, range extenders with a cubic capacity of at least 1000 to 1400 ccm have been proposed. The range extenders usually originate from engines for motor vehicles which have been previously available on the market and are therefore significantly larger than is actually necessary. As a result of their size, electric vehicles can reach an acceptable maximum speed and acceleration even when operating with a flat drive battery.
However, the large range extenders are very heavy and take up a lot of space in the vehicle. Relatively small range extenders have not been used until now since during operation with a flat drive battery they could only provide reduced driving performance (for example relatively low maximum speed and poor acceleration).